Nairobi: Somali pirates hijacked three Thai fishing vessels with 77 crew members over the weekend in one of their most daring raids so far, a maritime official said Tuesday.

Patrols by European Union warships since December 2008 to deter hijackings have done little to dent the enthusiasm for piracy among Somalis.

"This was in the Indian Ocean but far away from the east coast of Africa," said Andrew Mwangura, coordinator of the East African Seafarers' Assistance Programme. "This is the farthest hijacking to date. They are now operating near the Maldives and India."

Somali pirate attacks have continued apace and have spread south to the Seychelles and farther out towards India.

The European Union Naval Force said the three ships belonged to a Thai-based company, PT Interfishery, and were named Prantalay 11, 12 and 14. The Thai crew members were safe and well and the vessels were headed towards the Somali coast.

"These latest hijackings are the furthest east of any pirate attacks in the area since the start of EU NAVFOR's Operation Atalanta in December 2008, almost 600 miles outside the normal EU NAVFOR operating area," it said on its website.

According to the International Maritime Bureau, Somali pirates accounted for more than half the reported piracy incidents worldwide in 2009.